North Korea is keeping up its aggressive tone against the United States, warning it is, quote, "seriously examining a plan" to fire four missiles into the sea near the U.S. territory of Guam.

North Korea also called President Trump's statements a load of nonsense. This was after Trump promised fire and fury if North Korea keeps up its threats. Yesterday, Secretary of State Rex Tillerson struck a more reassuring tone.

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REX TILLERSON: What the president was doing is sending a strong message to North Korea in language that Kim Jong Un would understand because he doesn't seem to understand diplomatic language. I do not believe that there is any imminent threat, in my own view.

GREENE: Now, President Trump is hardly the first U.S. president to threaten war with North Korea. And the U.S. has long asked for help from China - to little avail though, as Max Baucus well knows. He's a former U.S. senator from Montana, and he was U.S. ambassador to China under President Obama, leaving that post in January. Ambassador Baucus, good morning.

MAX BAUCUS: Good morning, David.

GREENE: So do you agree with Secretary Tillerson that Americans don't have to worry - they can sleep well at night?

BAUCUS: I think we have to be concerned. But I do think it's wise to cool the rhetoric because escalating rhetoric, more often than not, leads to more escalation and closer to the tipping point of where something cataclysmic happens. So I think he's right to cool the rhetoric, but I also think that we have to recognize that China is a very proud country.

They have very deep interests - and they're self-interests, obviously. And they're clearly looking at what's happening over in North Korea with great alarm. And they probably have their own plans as to what they will do, should something untoward happen.

GREENE: What is China's interest here? I mean, take us into their thinking, if you can, at this moment.

BAUCUS: China cares about China. China cares about - the government cares about stability. That's more important than any other goal - maintaining stability. And to do that, they've got to keep the people happy and make sure they have jobs, et cetera. In addition, they care very much about potential unrest on their borders - Hong Kong, Taiwan, Western China, Zhejiang Province, and now they're looking at North Korea.

They do want - not want the peninsula to fall in the hands of the United States' control or South Korean control. That's - that would be anathema to them. And they're very hard-nosed. They will do whatever it takes to prevent that from happening.

GREENE: Well, they seem a little angry right now. I mean, China warned against remarks that could aggravate conflicts and escalate tensions, which as you just said, is exactly what they don't want. I mean, do you agree with the Chinese in a certain respect, that President Trump is not taking a constructive tone here?

BAUCUS: Well, I think that it's true that the United States and - and our president could take a much more constructive tone. John McCain was pretty close to the mark a day or two ago. And he said, you know, walk softly, carry a big stick, you know, as Teddy Roosevelt once said. We have to be, I think, very solid about this.

Only one country can solve this, and that's United States - China can't, Japan can't, neither can South Korea. We're the big boy on the block, and we have to act like leaders. We have to put the coalitions together and be very firm, while at the same time, showing that, hey, you know, we're going to protect our national security. We're not going to let anything happen that's going to damage our national security interests. But we have to start putting coalitions together.

I also think the time has come when we have to recognize that we're not going to be able to take out Kim Jong Un's nuclear capability. He's got bombs. He's got missiles. If - we're there. I think we have to, rather, start to manage it, as we did when China got the bomb, which, at that - you know, in the '60s, very much concerned us. Pakistan has the bomb, as does India. And it's - we have to manage it. And we have to start treating Kim Jong Un as an adult, and not treating him as a nut case. Because the more we treat him as an adult, the more, probably, he's going to act like an adult.

GREENE: Well, this is interesting. I mean, what you're saying is no small thing. I mean, there are some North Korea experts who say that that, you know, the U.S. is hamstrung by not being willing to accept North Korea as a nuclear power, although you don't get any hint from President Trump that he'd be willing to accept that right now. But you're saying that that - that is where the United States is, having to go beyond where we are and begin developing a long-term deterrence strategy.

BAUCUS: I think we have to start thinking very seriously about that because I, frankly, think that's where we are. And that means work with other countries, starting to talk to Kim Jong Un indirectly, through backdoor channels, maybe examining a freeze and with some other strong inspection regimes. I mean, there are a lot of ways to skin this cat. We just have to be very creative about how we do it.

GREENE: OK, that is Max Baucus, who is the former U.S. ambassador to China, also a former senator from the state of Montana. Ambassador, thanks so much for the time. We appreciate it.